高分子键联螯合钛酸酯的合成及催化性能研究

高分子催化剂以其独特的优点和功能日益受到人们的重视,目前均相催化剂的高分子固载化已成为催化剂研究的一个新领域。烷基钛酸酯是合成高沸点酯的有效催化剂,具有催化活性高、不易引起副反应等优点,但由于是均相催化反应,催化剂不易分离且不能回收及重复使用。本文首次将钛酸四丁酯与聚苯乙烯二乙醇胺树脂及异辛醇反应,制成一种稳定性良好的高分子键联螯合钛酸酯催化剂,对合成邻苯二甲酸二辛酯(DOP)具有良好的催化活性,且可重复使用。     

合成丙交酯的催化剂研究进展

丙交酯作为合成聚乳酸的重要中间体,它的制备效率是影响两步法聚合高分子量PLA的关键因素。寻找高效催化剂是其中一个重要的解决方案,本文就与日俱增交酯合成过程中不同催化剂体系的选择进行了综述,未来的工作应放在催化剂和制备效率上。     

新型固载化螯合钛酸酯催化合成高沸点酯的研究

新型固载化螯合钛酸酯催化合成高沸点酯的研究１）刘继红王春凤车丕智邢伯军孔祥球（哈尔滨师范大学化学系哈尔滨１５００８０）关键词固载化螯合钛酸酯催化剂高沸点酯酯化反应分类号Ｏ６４３．３２目前，固载化催化剂以其独特的功能日益受到人们的重视．均相催化剂的高分...     

马来酸二丁酯的杂多酸催化合成及动力学研究

考察了无机酸（如硫酸、盐酸）和新型杂多酸（如磷钨酸、硅钨酸）为催化剂,催化合成马来酸二丁酯的反应。结果表明,对于两类催化剂,其酯收率相当;确定了杂多酸催化合成马来酸二丁酯的反应级数为二级;PW12和SiW12杂多酸催化剂的表观活化能分别为60.4和57.0kJ/mol。     

非酸催化合成己二酸酯

本文利用大孔阳离子交换树脂，ＨＺＳＭ－５分子筛，锆酸酯为催化剂，合成了己二酸酯。对影响反应的因素进行了讨论，酯收率在９０％以上。     

树脂催化法合成糖醇酯的研究

利用大孔阳离子交换树脂为催化剂，催化合成乙酸糖醇酯，丙酸糠醇酯，丁酸糠醇酯，乙酸四氢糠醇酯，丙酸四氢糠醇酯，丁酸四氢糠醇酯，对影响反应的诸因素进行了讨论。     

苯酚和草酸二甲酯在不同分子筛催化下的酯交换反应

研究了以TS－1、H－ZSM－5、Hβ和H－丝光沸石等不同分子筛为催化剂，苯酚和草酸二甲酯酯交换合成草酸二苯酯反应。通过对催化剂进行吸附吡啶的红外光谱和NH3－TPD表征，考察了不同分子筛催化剂的酸性和酸强度对草酸二苯酯合成反应的影响，确定了催化剂上的弱酸中心是催化苯酚和草酸二甲酯酯交换合成草酸二苯酯反应的活性位，且催化剂的酸性中心越多，酸量越大，催化活性越好。催化剂上的强酸中心促进了副产物苯甲醚的生成。     

枞酸乙二醇单酯与双酯的合成工艺研究

采用L39^4正交实验研究了枞酸乙二醇单酯与双酯的合成工艺。探讨了反应温度、催化剂用量、反应物料摩尔比、反应时间等诸因素对转化率及选择性的影响。结果表明：反应温度与反应物料摩尔比分别对转化率及选择性具有最显著的影响。实验提供了枞酸乙二醇单酯与双酯的优化合成条件,在此基础上以松香为原料进行了验证。     

强酸性大孔树脂催化合成肉桂酸苄酯

以肉桂酸和苄醇为原料,用强酸性大孔树脂NKC-9作催化剂合成肉桂酸苄酯,确定了最佳的合成工艺为：0．01mol肉桂酸,0．08mol苄醇,酸醇比为1：8,催化剂用量1．52g,反应时间7h,肉桂酸的转化率为70．7％。大孔树脂作为清洁、环保的绿色酯合成催化剂,具有广阔的应用前景。     

螯合型二甘醇钛酸酯的合成及其催化性能研究

报导了两种新的螯合型二甘醇钛酸酯的合成方法，进行了ＩＲ和ＵＶ鉴定，并作为酯化反应催化剂催化合成了邻苯二甲酸二辛酯。研究了酯化反应转化率与反应时间、反应温度及催化剂用量的关系，探讨了催化剂结构与催化性能的关系。     

烟酸-卟啉二元化合物的合成、表征及其电化学性质

通过亲核取代反应合成了3个新的烟酸-卟啉二元化合物, 并用红外光谱、紫外-可见光谱、核磁共振氢谱、元素分析和质谱对化合物的结构进行确认, 通过循环伏安法研究了其电化学性质.     

SINGLE AND BINARY ADSORPTION PERFORMANCE OF SALICYLIC ACID AND 5-SULFOSALICYLIC ACID ONTO HYPERCROSSLINKED POLYMERIC ADSORBENTS

Single and binary adsorption behaviors of salicylic acid and 5-sulfosalicylic acid onto hypercrosslinked polymeric adsorbents, i.e. NDA-101 and NDA-99 were investigated. The Freundlich model can successfully describe all the adsorption isotherms tested, which indicates a favorable and exothermic adsorption process. The adsorption of salicylic acid relies on π-π interaction, while the electrostatic interaction further influences the adsorption of 5-sulfosalicylic acid onto NDA-99. The adsorptive capacity of salicylic acid on NDA-99 decreases but increases on NDA-101 with 5-sulfosalicylic acid as the background component in a binary solute system. The amount of 5-sulfosalicylic acid adsorbed was decreased with the increase in initial concentration of salicylic acid on both adsorbents. The competition for the adsorption sites is considered to be predominant in the solid-to-liquid interaction process. The adsorption selectivity of salicylic acid onto NDA-101 is higher than onto NDA-99 by more than an order of magnitude. Thus, combination technique involving NDA-101 followed by NDA-99 can be effectively applied to separate and recover salicylic acid and 5-sulfosalicylic acid from wastewater.     

Effect of binary extractants and modifier–diluents systems on equilbria of propionic acid extraction

Propionic acid is an important carboxylic acid widely used in chemical industries. The recovery from aqueous waste streams and fermentation broth is of research interest. Extraction of carboxylic acids by reactive extraction using extractant-diluent, mixed extractants in diluents and extractants in mixed diluents etc. are emerging areas of study. With this aim reactive extraction of propionic acid was carried out to study: (i) effect of binary extractants (tri-n-octylamine(TOA):tri-n-butylphosphate (TBP), TOA:Aliquat 336 and TBP:Aliquat 336), (ii) effect of modifier (1-decanol) in different diluents (kerosene, n-octane, n-heptane, petroleum ether, butyl acetate, MIBK, 2-octanol, dodecanol, hexane) and (iii) effect of phase volume. Improved extractions using binary extractants and binary diluents were observed. Since liquid–liquid extraction is dependent on effect of modifier concentration, effect of phase volume, presence of single or binary extractants and binary diluents, the study will be useful in the design of reactive extraction process for propionic acid recovery.     

Graft copolymerization induced by thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid in bulk

Thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid such as sodium or potassium poly(4-vinylbenzoate)-2-bromopropanoate [Na or K (PVBA-2-BPA)] in bulk were investigated. A methanol solution of binary acids was prepared by fixing the molar ratio of the repeating unit of polymeric acid to the fraction of brominated carboxylic acid. The binary salts were prepared by the neutralization of the binary acid solution. The product of the thermal reaction followed by esterification was identified as a graft copolymer containing PVBA in the main chain and polylactic acid in the side chain. The reaction of 1/15 K (PVBA-2-BPA) at 120 °C for 2 h yielded the highest percentage of grafting (300%). The grafting proceeded gradually for the initial 2 h and then somewhat. Reactivity of the K salt was higher than that of the corresponding Na salt. The thermal reaction of 1/10 K [polymethacrylate-2-BPA (PMA-2-BPA)] at 120 °C for 2 h also yielded a graft copolymer, and the percentage of grafting was 300%. However, reaction temperatures higher than 120 °C caused homopolycondensation of K 2-BPA prior to grafting, and homopolycondensation occurred prior to grafting in the reaction with Na (PMA-2-BPA). © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1877–1885, 2001     

超临界二氧化碳二元体系相平衡性质的研究

采用固定体积可视观察法测定了CO₂+甲苯、CO₂+环己烷、CO₂+正丁醛、CO₂+异丁醛、CO₂+甲醇及CO₂+乙醇二元体系的临界点性质,为超临界萃取和化学反应提供基础数据.在对二元体系相行为与单组分超临界相行为进行比较的基础上,对不同化学物质及不同配比的二元体系临界点与二氧化碳临界点之间的关系进行了讨论.     

比例方程法测定重稀土二元混合物

比例方程法是速差动力学分析中常用的方法,Яцимирский和Степаиов^[1,2]曾用此法测定稀土混合物。此法的缺点是需要准确控制时间,手工操作时误差较大。     

Shape tunable synthesis of anisotropic gold nanostructures through binary surfactant mixtures

In recent years, much effort has been made to produce gold (Au) nanorods of different sizes through the use of binary surfactant mixtures via a seed-mediated growth approach. However, how the ratio of two different surfactants influences the shape of the resulting Au nanoparticles remains to be elucidated. Here, we report the shape-controlled synthesis of Au nanoparticles using a binary surfactant mixture of CTAB (cetyltrimethylammonium bromide) and DDAB (didodecyldimethylammonium bromide) via a silver-assisted seed-mediated growth approach. Decreasing the CTAB/DDAB ratio results in a shape transition from Au nanorods to elongated tetrahexahedra and finally to Au bipyramids. The results showed significant improvement in the yield of Au bipyramidal type nanoparticles in different sizes (nm to μm) by using binary surfactant mixtures without any need for shape selection procedure. By varying the pH and concentration of ascorbic acid, we can control the shape and size of Au nanoparticles (i.e., truncated bipyramids, dogbones, and nanodumbbells) at fixed CTAB/DDAB ratios. A preliminary growth mechanism has been proposed based on the change in the mixed micelle soft-template induced by the increasing concentration of DDAB and reaction parameters (i.e., pH, concentration of ascorbic acid). These results constitute the advances in the understanding for synthesizing anisotropic Au nanoparticles of tunable optical properties via engineering the design of a soft-template. These anisotropic Au nanoparticles, especially, bipyramids of different morphologies and sizes are potential candidates for the enhancement of the optical response and developing label-free biosensing devices.     

N,N-二乙基丙烯酰胺与丙烯酸在聚丙烯薄膜表面光接枝制备二元接枝膜及其温度、pH值敏感特性研究

以二苯甲酮为引发剂,聚丙烯薄膜(CPP)为基材,通过紫外光接枝的方法制备了具有温度和pH值双重敏感特性的聚N,N-二乙基丙烯酰胺(PNDEA)与聚丙烯酸(PAA)二元接枝膜.在PNDEA一次接枝膜的制备过程中,引发剂与单体配比相同时,本体接枝方法的接枝速率在反应初期明显高于溶液接枝方法;采用溶液法时,增大引发剂与单体配比等可提高接枝率.用本体法所制得的PNDEA一次膜光活化接枝PAA时接枝速率较溶液法高,并且能够实现较高的PAA接枝率.用红外光谱(FTIR)、X射线光电子能谱化学分析(ESCA)对接枝层组成的表征结果证实了二元接枝层的存在.在不同温度下,PNDEA一次接枝膜的FTIR谱图中酰胺Ⅰ带特征吸收峰发生位移表明它具有温度敏感特性.用扫描电子显微镜(SEM)对PNDEA接枝层表征结果表明,用不同接枝手段所制备的接枝膜具有不同的表面形貌.通过吸水率测定研究了二元接枝膜的温度及pH值敏感特性.     

利用石墨烯-炭黑组成的二元碳载体增强甲酸在钯催化剂上电化学氧化的活性

本文采用"一锅法"将氧化石墨烯(GO)、炭黑(C)和钯离子用NaBH4共还原,制备了石墨烯-炭黑二元载体(Gr-C)负载的钯催化剂(20%Pd/Gr-C),用于催化甲酸的电氧化反应.电化学测试结果表明,前驱体GO和C的质量比为3:7的Pd/Gr0.3C0.7催化剂催化活性最好,它的峰电流密度(102.14 mA mgPd-1)约为Pd/C催化剂(34.40 mA mgPd-1)的3倍,为钯/石墨烯催化剂(Pd/Gr,38.50 mA mgPd-1)的2.6倍.甲酸在Pd/Gr0.3C0.7催化剂电极直接氧化时的峰电位比Pd/C催化剂的峰电位负移约120 mV,比Pd/Gr催化剂的峰电位负移约70 mV.采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、拉曼光谱、电感耦合等离子发射光谱(ICP-AES)等手段对催化剂进行了表征.从SEM图像可以观察到,球形的炭黑团簇聚集在具有褶皱的石墨烯面上,形成了炭黑团簇/石墨烯三维立体结构,有效地抑制了相邻石墨烯层在范德华力作用下的吸引聚集和堆叠造成的石墨烯表面积减小,减小了单层石墨烯叠合成为多层石墨所造成的导电性损失,避免了相邻石墨烯片叠合形成封闭空间,有助于反应物和产物分子的运动.载体的三维结构使反应物分子更容易到达钯纳米粒子,有利于催化性能的提高.XPS结果也证实了二元Gr-C载体对Pd催化的促进作用.Pd/Gr0.3C0.7催化剂的Pd 3d5/2峰发生了右移,表明Pd 3d电子结合能正移,Pd 3d电子云密度降低.具有较低的3d电子云密度的Pd不易与甲酸氧化过程中吸附的中间体(COOH)ads结合,钯催化剂上(COOH)ads表面覆盖率降低,从而使甲酸更容易直接脱氢氧化生成CO2,有利于甲酸通过直接途径进行电化学氧化.与Pd/C,Pd/Gr相比,Pd/Gr0.3C0.7催化剂对甲酸电氧化有最好的催化活性.Pd/Gr0.3C0.7催化剂优异的催化活性可归因于其内在的三维纳米结构:炭黑团簇有效地抑制了石墨烯纳米片的聚集,保持了其大的比表面积和高导电性,促进了反应物和产物分子的运动.此外,Pd纳米粒子与二元载体之间的强相互作用降低了Pd的3d电子云密度,使甲酸氧化主要经直接途径进行.本文证实了钯金属和石墨烯-炭黑二元载体之间的强相互作用,提供了简单和高性价比的方法以提高钯基催化剂的活性,有利于工业化的应用.     

Evaluation of excess molar polarization in binary mixtures of Polar–Nonpolar liquids

Excess molar polarization in the binary mixture of polar solutes (acetic acid, n-tributyl phosphate) in nonpolar solvents (benzene, tetrachloromethane, p-xylene) is evaluated with the help of our proposed equation. The results have been compared with those obtained from a previously proposed equation. It is observed that our proposed equation is more accurate to interpret the liquid structure and molecular association in the binary liquid mixtures.